Used a habituation-dishabituation procedure to test ability of 4-, 5-, and 7-month-olds to differentiate between a subjective ellipse and a nonsubjective pattern that were constructed by displacing the inducing elements of the illusory figure. Found that even 4-month-olds discriminated between the subjective ellipse and nonillusory display. This behavior was not generated by certain local differences between the test patterns. (Author/KB)